Information Processing Apparatus and Power Saving Effect Display Method

1. An information processing apparatus comprising: a power supply module configured to generate a system power to be supplied to the information processing apparatus in either of a first mode and a second mode, the power supply module generating the system power from an externally-supplied utility power in the first mode, the power supply module generating the system power from a power received from a built-in battery in the second mode; a history storage module configured to cumulatively store: an imaginary-saved power calculated based on a difference between a reference power usage and a current power usage; a power generation mode of the power supply module in correlation with the imaginary-saved power, the power generation mode being the first mode or the second mode; and a date and time at which the imaginary-saved power and the power generation mode are obtained; the history storage module further storing a first target power savings amount set for the first mode and a second target power savings amount set for the second mode; a sum module configured to calculate: a first power savings amount by adding values of the imaginary-saved power correlated with the first mode within a given period; and a second power savings amount by adding values of the imaginary-saved power correlated with the second mode within the given period; and a subtraction module configured to calculate: a first remaining power savings amount by subtracting the first power savings amount from the first target power savings amount; and a second remaining power savings amount by subtracting the second power savings amount from the second target power savings amount; an image generator configured to generate an image indicating a degree of power saving attainment for each of the first mode and the second mode on a display device based on the first and second remaining power savings amounts.

2. The apparatus of claim 1 , wherein the image comprises a figure comprising a color gradually varying from red to green as each of the first and second remaining power savings amounts comes closer to zero.

3. The apparatus of claim 1 , wherein the image comprises at least one of: numerical information of the first and second power savings amounts; numerical information of a carbon dioxide reduction amount calculated based on the first and second power savings amounts and a per-unit carbon dioxide emission amount of respective power sources; and numerical information of an electricity charge reduction calculated based on the first and second power savings amounts.

4. An apparatus group comprising: a plurality of information processing apparatuses, each information processing apparatus comprising: a power supply module configured to generate a system power to be supplied to the information processing apparatus in either of a first mode and a second mode, the power supply module generating the system power from an externally-supplied utility power in the first mode, the power supply module generating the system power from a power received from a built-in battery in the second mode; a history storage module configured to cumulatively store: an imaginary-saved power calculated based on a difference between a reference power usage and a current power usage; a power generation mode of the power supply module in correlation with the imaginary-saved power, the power generation mode being the first mode or the second mode; and a date and time at which the imaginary-saved power and the power generation mode are obtained; the history storage module further storing a first target power savings amount set for the first mode and a second target power savings amount set for the second mode; at least one of the information processing apparatuses further comprises: a group history storage module configured to store the imaginary-saved powers in all of the information processing apparatuses and the date and times thereof; a group sum module configured to calculate: a first power savings amount by adding values of the imaginary-saved powers in all of the information processing apparatuses correlated with the first mode within a given period; and a second power savings amount by adding values of the imaginary-saved powers in all of the information processing apparatuses correlated with the second mode within the given period; a first group target power savings amount by adding values of the first target power savings amount in all of the information processing apparatuses within the given period; a second group target power savings amount by adding values of the second target power savings amount in all of the information processing apparatuses within the given period; and a subtraction module configured to calculate: a first remaining power savings amount by subtracting the first power savings amount from the first group target power savings amount; and a second remaining power savings amount by subtracting the second power savings amount from the second group target power savings amount; a group image generator configured to generate an image indicating a degree of power saving attainment for each of the first mode and the second mode on a display device based on the first and second remaining power savings amounts.

5. A power saving effect display method comprising: generating a system power to be supplied to a plurality of information processing apparatuses in either of a first mode and a second mode, wherein in the first mode the system power is generated from an externally-supplied utility power, wherein in the second mode the system power is generated from a power received from a built-in battery; calculating imaginary-saved powers based on a difference between a reference power usage and a current power usage of the plurality of information processing apparatuses; storing the calculated imaginary-saved powers, power generation modes in correlation with the imaginary-saved powers, the power generation modes being the first mode or the second mode, and a date and time at which the imaginary-saved powers and the power generation modes are obtained into a history storage module; further storing a first target power savings amount set for the first mode and a second target power savings amount set for the second mode; calculating a first power savings amount by adding values of the imaginary-saved powers in all of the information processing apparatuses correlated with the first mode within a given period; calculating a second power savings amount by adding values of the imaginary-saved powers in all of the information processing apparatuses correlated with the second mode within the given period; calculating a first group target power savings amount by adding values of the first target power savings amount in all of the information processing apparatuses within the given period; calculating a second group target power savings amount by adding values of the second target power savings amount in all of the information processing apparatuses within the given period; calculating a first remaining power savings amount by subtracting the first power savings amount from the first group target power savings amount; calculating a second remaining power savings amount by subtracting the second power savings amount from the second group target power savings amount; and displaying an image on a display device indicating a degree of power savings attainment for each of the first mode and the second mode on based on the first and second remaining power savings amounts.

6. The apparatus of claim 1 , wherein the given period comprises at least one of: a month up to a current time point; a year up to the current time point; and an arbitrary term starting from a given starting time point to a given end time point except for the current time point.

7. The apparatus of claim 1 , wherein the information processing apparatus and another information processing apparatus having substantially similar functionality are connected to form a group, wherein the history storage module is further configured to cumulatively store: a group imaginary-saved power calculated based on a difference between a group reference power usage and a group current power usage; and a date and time at which the group imaginary-saved power is obtained the history storage module further storing a group target power savings amount; wherein the sum module is further configured to calculate: a group power savings amount by adding values of the group imaginary-saved power the given period; wherein the subtraction module is further configured to calculate: a group remaining power savings amount by subtracting the group power savings amount from the group target power savings amount; wherein the image generator is further configured to generate another image indicating a degree of power saving attainment for the group, based on the group remaining power savings amount.